<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>标题标签</title>
</head>
<body>
  <!-- 都是块级元素 -->
  <h1 id="one">我是一级标题</h1>
  <!-- br-强制换行 -->
  <br>
  <h2>我是二级标题</h2>
  <!-- hr-分割线 -->
  <hr>
  <h3>我是三级标题</h3>
  <h4>我是四级标题</h4>
  <h5>我是五级标题</h5>
  <h6>我是六级标题</h6>
  <!-- p-段落标签 -->
  <p>我是p标签</p>

  
</body>
</html>